Evaluation of radiographic cardiac dimensions in apparently healthy medium-breed dogs

Vertebral heart score is the standard method used to diagnose cardiac disorders in dogs; however, some veterinary radiologists adopt cardiothoracic ratio used in humans to diagnose cardiac disorders in dogs. This study was aimed to investigate the relationship between the vertebral heart score and the cardiothoracic ratio, which would improve the accuracy in the diagnosis of cardiac anomalies in dogs. Vertebral heart score and cardiothoracic ratio were obtained from the left lateral and ventrodorsal radiographic projections of the thoracic region, respectively. Mean±SD values for vertebral heart score and cardiothoracic ratio in Nigerian indigenous dogs were 9.3±0.44 vertebrae and 0.46±0.04, respectively. Pearson's coefficient correlation between vertebral heart score and cardiothoracic ratio in dogs revealed a significant (p=0.03) and positive (r²=0.61) relationship. This study revealed a good relationship between the radiographic cardiac dimensions, therefore, the cardiothoracic ratio can be used as a reliable radiographic cardiac index in a medium-size breed of dogs.